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Original Year
 1989
# of pieces
 240
Categories
 Construction Equipment:  Forklifts
Dimensions
 28(L)x12(W)x19(H)
Features
 Steering (rear), Tilting forks,
Lifting forks
Other Views

8835 Forklift
iso revolve
Click the image to download the LDraw file of this model.
Model by Benjamin Wendl
Set 8835 was released in 1989 as the 3rd Technic forklift.   This forklift features rear wheel steering as well as forks which raise, lower, and tilt.  Raising and lowering is accomplished via a worm driven chain.

This model is similar in appearance and function to 8843 except that the fork mechanism is gear driven rather than pneumatic.  It is also the first of only a few models to use the new specialized fork parts.  This model has a problem with the forks jamming while being driven up or down.  The parts which react the cantilever moment are very small and tend to get stuck, requiring them to be manually straightened before the movement can continue.

Features
Steering
The rear wheels can be steered using an overhead "hand of god" control.  The overhead control drives an axle connected to a pair of 14 tooth bevel gears.   The second axle drives a rack via an 8 tooth pinion gear.  The steering mechanism itself uses the steering arms and toothed links as shown in the computer image.

The steering knob is designed to look like a flashing light.

 steering    steer
Click for an animation of the steering in motion.
Forks
The forks can be raised and lowered via a crank of the right side.  The computer image is color coded to follow the path of torque.  The input crank turns an axle (red) with a worm gear.  A 24 tooth spur gear (blue axle) is driven by this.  Torque passes through a set of 16 tooth spur gears and into a 24 tooth crown (green axle).  The crown drives an 8 tooth pinion which is connected to the axle driving the lift chain.  The lift chain stretches across the frame between two 16 tooth gears and has one wide link (yellow).  This link lifts the forks.

The final gear ratio is 12:1.  The worm gear prevents the system from backdriving because the axial friction is higher than the backdriving torque due to the screw pitch angle.

The moment created by the cantilevered weight is reacted by a force couple:  the upper forward load is reacted by a set of 2x2 corner plates on the back of the vertical fork assembly, and the lower aft load is reacted by contact of the lower tiles against the vertical fork assembly.  This system fits a  bit too snugly and tends to jam.
forks    forks
Click for an animation of the forks lifting.
Fork Tilting
The entire fork and lift assembly can also be tipped forward to aid in picking up a pallet from the ground.  A lever on the left side made of a new liftarm turns a pulley wheel used as a crank.  A link attached to the crank connects to the vertical structural assembly which pivots about an axle on its base.  Because the link travels over center on the pulley wheel, weight on the forks will not tip the mechanism when locked (see animation).
 tilt    tilt
Click for an animation of the forks tilting.
Wheels and Tires
This set has 4 of the 13x24 Model Team wheels. 		Wheels
 

Other Views
Side View
side view
 Top View
top view
Front View
front view
Back View
back view
Computer Render
Render

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